Data from 2B4 (CD244) Signaling by Recombinant Antigen-specific Chimeric Receptors Costimulates Natural Killer Cell Activation to Leukemia and Neuroblastoma Cells

Abstract

<div>Abstract<p><b>Purpose:</b> Novel natural killer (NK) cell–directed strategies in cancer immunotherapy aim at specifically modulating the balance between NK cell receptor signals toward tumor-specific activation. The signaling lymphocyte activation molecule–related receptor 2B4 (CD244) is an important regulator of NK cell activation. We investigated whether 2B4-enhanced activation signals can redirect the cytolytic function of human NK cells to NK cell–resistant and autologous leukemia and tumor targets.</p><p><b>Experimental Design:</b> <i>In vitro</i>–stimulated NK cells from healthy donors and pediatric leukemia patients were gene modified with CD19 or G<sub>D2</sub>-specific chimeric receptors containing either the T-cell receptor ζ or 2B4 endodomain alone or combined.</p><p><b>Results:</b> Chimeric 2B4 signaling alone failed to induce interleukin-2 receptor up-regulation and cytokine secretion but triggered a specific degranulation response. Integration of the 2B4 endodomain into T-cell receptor ζ chimeric receptors significantly enhanced all aspects of the NK cell activation response to antigen-expressing leukemia or neuroblastoma cells, including CD25 up-regulation, secretion of IFN-γ and tumor necrosis factor-α, release of cytolytic granules, and growth inhibition, and overcame NK cell resistance of autologous leukemia cells while maintaining antigen specificity.</p><p><b>Conclusion:</b> These data indicate that the 2B4 receptor has a potent costimulatory effect in NK cells. Antigen-specific 2B4ζ-expressing NK cells may be a powerful new tool for adoptive immunotherapy of leukemia and other malignancies.</p></div>